1. Field of the Invention
This invention relates to a sewing machine control device.
2. Background Art
A conventional motor-operated sewing machine is designed to rotate a machine-driving means by operating a clutch to transmit the rotational power of a motor to the machine when a pedal control switch is turned on. In order to quickly stop the machine being driven when a switch is turned off, the clutch is released to isolate the rotation of the machine from that of the motor and a brake is applied. It may be considered as a means for measuring the operating time of the machine to total the periods of time during which the control switch is kept on.
It is, however, not accurate to use the period of time during which the control switch is kept on as the operating time of the machine, since, even after the control switch has turned off, the machine is kept on rotating at a lower speed so that the needle reaches a predetermined position with a desired accuracy. For this reason, a difference unavoidably arises between the actual and measured operating time and the disadvantage is that not only work control but also maintenance time length cannot properly be determined.